This invention relates to an electromagnetic interference ("EMI") shielding device for a video display unit ("VDU") and methods for making the same. More particularly, this invention relates to an EMI shielding device in which an electrically conductive transparent screen is in electrically conductive contact with the "face" or viewing surface of the cathode ray tube and the electrically conductive cabinet.
It is well known that operation of a cathode ray tube results in a build up of static electricity on the face or display portion of the cathode ray tube. This build up of static electricity causes a disadvantageous accumulation of foreign particles on the faceplate of the video display unit as well as the VDU operator. In addition, it is advantageous to provide an antiglare treatment for the viewing surface of VDU displays. Antiglare treatments are typically accomplished by causing the outermost viewing surface to have a slight texture (non flat) surface. In many applications, this antiglare feature is achieved by mechanically or chemically etching a textured surface into the viewing face of the cathode ray tube itself. This process may be relatively expensive. In other antiglare applications, a texture is imparted to a faceplate of rolled plastic which may be sold separate from the VDU as a feature added by the user.
It has recently become known that EMI shielding may be provided by knitted or woven wire mesh which is fully laminated between glass and/or plastic substrates. For example, see the brochure by Chomerics entitled "Chomerics Optical Products", date unknown. While this may be effective means for reducing EMI and the build up of static electricity on the face of a video display unit, shielding of this type is typically for military/aerospace application and it requires relatively complex manufacturing procedures.